Using Local Infrasound to Estimate Seismic Velocity and Earthquake Magnitudes
Using Local Infrasound to Estimate Seismic Velocity and Earthquake Magnitudes
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DOI：
10.1785/0120220237
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发表时间：
2023-04
影响因子：
3
通讯作者：
K. Macpherson;D. Fee;J. R. Coffey;Alex J. C. Witsil
中科院分区：
文献类型：
--
作者：
K. Macpherson;D. Fee;J. R. Coffey;Alex J. C. Witsil
接收器附近的地震地面运动与大气耦合，产生次声传感器可检测到的压力扰动。这些所谓的本地次声信号穿过非常短的源到接收器的路径，使得它们经常表现出显着的相关性与地震速度波形在配置的地震台站，并且存在一个简单的关系之间的垂直地震速度和压力的时间序列。这项研究利用阿拉斯加的大型区域次声传感器网络来研究阿拉斯加几次轻微到巨大地震的当地次声。我们估计地震速度时间序列的次声压力记录，并使用这些转换的次声记录来计算地震震级。这种技术除了在压力传感器上记录地震速度的新奇之外，还具有潜在的实用性。由于当地的次声振幅从地面运动是小的，它是可能的，恢复地震速度在并置的网站，宽带地震仪已经削减。次声导出的地震震级与地震导出值具有良好的一致性。这种从次声传感器计算地震震级的概念验证演示表明，次声传感器可以用作代理垂直分量地震仪，为现有的地震技术提供新的数据集。由于单传感器次声台站相对便宜，而且正变得无处不在，因此可以利用现成的传感器平台，将这种技术用于扩大现有的区域地震网络。
Earthquake ground motions in the vicinity of receivers couple with the atmosphere to generate pressure perturbations that are detectable by infrasound sensors. These so-called local infrasound signals traverse very short source-to-receiver paths, so that they often exhibit a remarkable correlation with seismic velocity waveforms at collocated seismic stations, and there exists a simple relationship between vertical seismic velocity and pressure time series. This study leverages the large regional network of infrasound sensors in Alaska to examine local infrasound from several light to great Alaska earthquakes. We estimate seismic velocity time series from infrasound pressure records and use these converted infrasound recordings to compute earthquake magnitudes. This technique has potential utility beyond the novelty of recording seismic velocities on pressure sensors. Because local infrasound amplitudes from ground motions are small, it is possible to recover seismic velocities at collocated sites where the broadband seismometers have clipped. Infrasound-derived earthquake magnitudes exhibit good agreement with seismically derived values. This proof-of-concept demonstration of computing seismic magnitudes from infrasound sensors illustrates that infrasound sensors may be utilized as proxy vertical-component seismometers, making a new data set available for existing seismic techniques. Because single-sensor infrasound stations are relatively inexpensive and are becoming ubiquitous, this technique could be used to augment existing regional seismic networks using a readily available sensor platform.